I'll gladly play Apple processor prices for an Apple processor, but I'm not going to pay Apple PC prices for an Apple PC when all I really want is the CPU.
I guess Apple doesn’t want to be Intel. It is like the old Kelloggs adverts “we don’t make cereal for anyone else”. Alluding to those brands that use the same cereal at a marked up price and resell it to a supermarket brand to sell at a lower price in a plain box.
It's an SoC; what do you think you're paying for besides the CPU? The whole rest of the computer (for a Mac Mini, at least) is worth maybe $50.
Except if you want 32gb ram and 2tb disk space, they charge well in excess of what anyone else (for the most part) is able to charge for similar upgrades.